Question

Suppose that you wish to offer a voice over IP wireless service.
The target packet
error rate (or drop rate) is 10^3 and you determine that if the
signal is confined to
within a coherence band, about 20% of the packets are dropped due
to fading. To
solve this problem, you introduce frequency diversity by spreading
the signal over
multiple coherence bands.

a. If each coherence band is 100 kHz and experiences independent
fading, about how
much bandwidth does your system require? (Hint: calculate the
probability that at
least one of the coherence bands will not be faded according to the
slides on selection
diversity.)

b. Now suppose that an error correction code is introduced into the
original
(narrowband) system that reduces the packet drop rate to 5%. How
does this change
the bandwidth your system requires?